Tag Archives: sperm

When it comes to parenting, some animals will go the extra mile. Possums, for example, have their young clinging on as they trundle around. Kangaroos give birth to immature young that they keep in a pouch until it’s bursting at the seams. Humans let 30 year old offspring move back in.

The fish above has a mouthful of eggs. It’s a cichlid. And some species of cichlid will go the extra…mouthful to protect their eggs. They are so worried about the predation of their eggs that the females lay eggs, circle around, and then immediately gobble them up, holding them in their mouths until the fry hatch, and often even longer, until they are big enough to make it on their own.

However, it turns out that the female fish are in such a rush to pick up their eggs, they sometimes don’t even give them time to get fertilized! Holding a mouth of unfertilized eggs seems like kind of a waste. But the males have figured out not just how to get fertilization to happen…they got some oral sex out of the bargain.

What you all were waiting for has finally come! Yeah.Sperm maturation and ejaculation
OK!! So the last time I was over here at Neurotopia we were talking about sperm in their infancy. We discussed spermatogenesis — how we got from a diploid spermatogonial stem cell to a haploid spermatid — and then spermiogenesis — the process by which the spermatids acquire the features of spermatozoa: tails, acrosomes and the like.
We stopped there when the sperm had just graduated from diapers to their big kid undies, and we’ll pick up where we left off.

Well well well. Here we are. It’s Friday. And we’ve been talking about SPERM ALL WEEK.
What to do…what to do… Nel-Themaat et al. “Quality and freezing qualities of ﬁrst and second ejaculates collected from endangered Gulf Coast Native rams” Animal Reproduction Science, 2006.
Heh.
So it turns out that the people who wrote the study Sci covered the other week wrote ANOTHER one. Also, it turns out the eland is not endangered, but the other species they were working with, the Gulf Coast Native Sheep, IS endangered. Though it’s a rather odd beastie, in that it originally was from a population of European sheep brought over to the US, which escaped, went feral, and is now considered its own variety. This is an important sheep to look at in particular because the Gulf Coast Sheep has become adapted to living in a moist environment (as some of you may be aware, the southeast of the US is very moist, in some areas is it entirely IMPOSSIBLE to get all the mildew out of your house EVER), being less sensitive to parasites and less sensitive to fungal problems like foot rot. This means that if you wanted to, say, work with sheep in humid environments (sheep are often introduced domestically for very poor areas, and the southeastern US is apparently trying to reintroduce them. It is Sci’s hope that they might eat the dang kudzu), you might want to take a look at these Gulf Coast sheep, and maybe steal of their useful genes for your benefit. And of course if you are going to steal some genes and breed some of these Gulf Coast sheep into your stock you need…some sperm.

Multiple ejaculates. Because once is never enough.
Oh and also:

For those who don’t know about kudzu. It SUCKS. A lot. There’s a house under there, under the lump in the middle. Really. It was introduced (I think from Japan) as something for cows and sheep and stuff to forage on. Also, it was apparently ornamental (*snort*). There was only one problem with the plant.
Cows WON’T EAT IT. I mean, they’ll eat it if they’re STARVING, but they don’t enjoy it. Goats don’t either. NO ONE DOES. And kuzdu can grow like…kudzu. In the southeast, it takes over EVERYTHING. Every spring and summer becomes a war on the kudzu. A sheep that would eat this crap would get a grateful hug from Sci every day of it’s little life. It would also get VERY fat.
Anyway. Back to semen. I know what you guys REALLY want to hear about.

Hello and welcome to Guest Post TWO! And Sci is so glad that Ambivalent Academic is covering meiosis, because I sure as heck didn’t want to do it. 🙂Male Reproduction Part II – Spermatogenesis
Last we left off we took a basic tour through the male reproductive tract in the way in which a sperm will encounter it. So now let’s talk sperm!
How are they made? How do they make their way through all these convoluted tubes? How do they finally achieve all their spermy aspirations?
Sit down and buckle up – I’m about to tell you.

Sci may have hinted that there were guest posts coming up in the near future. After that long series on female reproductive anatomy, Sci thought it would only be fair to let the dudes have some information as well. Unfortunately, Sci’s knowledge of the male reproductive system is related almost entirely to hilarious things like bicycle accidents and pens, and so she had to turn to someone a little more knowledgeable on the actual way the system works.
And so, into the breach has stepped the intrepid Ambivalent Academic! She is here to deliver the sperm, the semen, the testicles, and all other articles of male anatomy right to your computer! And it even comes without malware!
So let’s have a big round of applause for Ambivalent Academic, and Male reproductive anatomy: Part 1.

And we’re back with part 4 of Sci’s brand spanking new series on female reproduction!! This one’s going to be a whopper, fertilization and pregnancy is a lot to cover, and so it will be very basic and divided into two posts, though less basic than the “baby in your tummy” bit that Sci learned when she was small.

So here we go, basic fertilization and early pregnancy, starting with your friend, the sperm:

Sci will go ahead and put it out there: she hates smoking (I mean tobacco). It’s gross. It smells. You NEVER get that freakin’ smell out of your hair. And your teeth get all nasty. Not to mention to horrendous side effects, things like cancer and cardiovascular problems and death…yeah, those are bad, too.

So anyway, I think we all know smoking is bad for you. Addictive, cancer-causing, the addictive part is particularly bad, nicotine has an extremely high number of reinforcers obtained per drug session (you can only take one line of cocaine at a time, really, but a cigarette has you occupied, puffing away for a good few minutes). But now men have ANOTHER reason not to smoke: your little swimmers don’t like it. Kumosani, et al. “The influence of smoking on semen quality, seminal microelements, and Ca2+-ATPase activity among infertile and fertile men.” Clinical Biochemistry, 2008.

Sci will admit that the sperm paper she picked for this week really is an excuse to use this image:

But really, sperm swimming is an important questions in terms of fertility. An ovum is only viable for about 24 hours, and a female only produces one per month. Sperm are viable for a little longer than that, but still, timing is rough. And once you get past the timing, you get into sperm getting lost, sperm swimming in circles, sperm getting stuck in the vaginal mucosa, and sperm getting to the egg only to be thwarted by the zona pellucida and corona radiata (the corona radiata is a group of cells surrounding the egg, while the zona pellucida is a tough, thick protein lattice on the outside of the egg, inside the corona radiata. Tough barriers).

So when it comes down to it, it takes more than a straight swimmer to make it to the egg. But what, exactly, does it take? Force, et al. “Membrane fluidity and lipid content of human spermatozoa selected by swim-up method”. International Journal of Andrology, 2001.